1. Field of the Invention
The present invention relates to an adjustment technique for backlight source of a display device. More particularly, the present invention relates to a technique for dynamically controlling backlight source, which may control gray levels of pixels of a display panel to reduce power consumption of the backlight source.
2. Description of Related Art
A display such as a liquid crystal display (LCD) using a passive light source generally requires a backlight module to function as the light source. FIG. 1 is a schematic diagram illustrating a display mechanism of a conventional LCD. Referring to FIG. 1, a conventional LCD includes a display panel 102 comprising a pixel array for displaying an image. Each pixel of the pixel array has three primary colors of red, green and blue. For example, the pixel is composed of three sub-pixels with the three primary colors of red, green and blue, and a transmissive control unit Tcon 104 is used for controlling transmissivities of the three sub-pixels with red, green and blue colors according to a required gray level of the image.
Since the LCD panel 102 is not luminous itself, a backlight module 100 is required for providing a white light beam. The white light beam passing through the three sub-pixels with red, green and blue colors forms the light beams with the three primary colors according to the transmissivities of the sub-pixels, and then the light beams are combined to form a light beam with a desired color, and the light beam with the desired color is then provided to a human eye 106 for observation.
According to a conventional display method, the backlight module 100 provides the white light beam with a fixed intensity, and the luminances of the pixels vary by changing gray levels of the pixels, so as to achieve a variation of displaying color. In this case, light emitted from the backlight module 100 maintains a highest luminance, and a duty cycle of the backlight module 100 is 100%. Therefore, power consumption of the conventional method is relatively great, and should be reduced to save power. More particularly, a mobile device using a battery particularly requires the energy saving effect for prolonging a working time of the device.